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Test Detects Immune-Modifying Poultry Protein

A previously little-understood protein could be used to monitor poultry health, according to studies by Agricultural Research Service (ARS) scientists.

When chickens and turkeys become infected with different bacterial and viral diseases, the resulting inflamation causes physiological changes, including decreases or increases in concentrations of some serum proteins called acute phase proteins (APPs). These amplify immune response by recruiting other cells to the inflamation site to provide early infection resistance. APP concentrations remain detectable in the blood until recovery, offering potential for diagnostic or prognostic tools for poultry producers.

Ovotransferrin, an iron-binding protein, is abundant in poultry blood and eggs. Scientists at the Poultry Production and Products Safety Research Unit in Fayetteville, Ark., found that blood concentrations of ovotransferrin (OTF) increase in chickens with infections. They determined that OTF is a major APP in chickens. Its antimicrobial activities are probably related to its ability to block the availability of iron, an essential element for bacterial growth.

OTF was identified and characterized by Hang Xie, a former graduate student working in the ARS laboratory.

The researchers developed a test, called an enzyme-linked immunoassay, to detect and measure the levels of OTF in the blood. They believe these OTF levels can be used as an indicator of health problems in poultry, according to Narayan Rath, a research physiologist at the Fayetteville lab.

A better understanding of the roles of disease-modifying APPs in serum could lead to new approaches for improving natural disease resistance in poultry--such as developing genetic markers that breeders can use to select poultry able to more effectively fight off disease.

Companies have shown interest in working with the laboratory to license the enzyme-linked test. Other potential collaborations involve developing a diagnostic marker based on OTF to determine the health of birds during meat inspections, either before or after slaughter.